/*
 * hostapd / IEEE 802.11 authentication (ACL)
 * Copyright (c) 2003-2012, Jouni Malinen <j@w1.fi>
 *
 * This software may be distributed under the terms of the BSD license.
 * See README for more details.
 *
 * Access control list for IEEE 802.11 authentication can uses statically
 * configured ACL from configuration files or an external RADIUS server.
 * Results from external RADIUS queries are cached to allow faster
 * authentication frame processing.
 */

#include "utils/includes.h"

#include "utils/common.h"
#include "utils/eloop.h"
#include "crypto/sha1.h"
#include "radius/radius.h"
#include "radius/radius_client.h"
#include "hostapd.h"
#include "ap_config.h"
#include "ap_drv_ops.h"
#include "ieee802_11.h"
#include "ieee802_1x.h"
#include "ieee802_11_auth.h"

#define RADIUS_ACL_TIMEOUT 30

struct hostapd_cached_radius_acl {
	struct os_reltime timestamp;
	macaddr addr;
	int accepted;				/* HOSTAPD_ACL_* */
	struct hostapd_cached_radius_acl *next;
	u32 session_timeout;
	u32 acct_interim_interval;
	int vlan_id;
	struct hostapd_sta_wpa_psk_short *psk;
	char *identity;
	char *radius_cui;
};

struct hostapd_acl_query_data {
	struct os_reltime timestamp;
	u8 radius_id;
	macaddr addr;
	u8 *auth_msg;				/* IEEE 802.11 authentication frame from station */
	size_t auth_msg_len;
	struct hostapd_acl_query_data *next;
};

#ifndef CONFIG_NO_RADIUS
static void hostapd_acl_cache_free_entry(struct hostapd_cached_radius_acl *e)
{
	os_free(e->identity);
	os_free(e->radius_cui);
	hostapd_free_psk_list(e->psk);
	os_free(e);
}

static void hostapd_acl_cache_free(struct hostapd_cached_radius_acl *acl_cache)
{
	struct hostapd_cached_radius_acl *prev;

	while (acl_cache) {
		prev = acl_cache;
		acl_cache = acl_cache->next;
		hostapd_acl_cache_free_entry(prev);
	}
}

static void copy_psk_list(struct hostapd_sta_wpa_psk_short **psk, struct hostapd_sta_wpa_psk_short *src)
{
	struct hostapd_sta_wpa_psk_short **copy_to;
	struct hostapd_sta_wpa_psk_short *copy_from;

	/* Copy PSK linked list */
	copy_to = psk;
	copy_from = src;
	while (copy_from && copy_to) {
		*copy_to = os_zalloc(sizeof(struct hostapd_sta_wpa_psk_short));
		if (*copy_to == NULL) {
			break;
		}
		os_memcpy(*copy_to, copy_from, sizeof(struct hostapd_sta_wpa_psk_short));
		copy_from = copy_from->next;
		copy_to = &((*copy_to)->next);
	}
	if (copy_to) {
		*copy_to = NULL;
	}
}

static int hostapd_acl_cache_get(struct hostapd_data *hapd, const u8 *addr, u32 *session_timeout, u32 *acct_interim_interval, int *vlan_id, struct hostapd_sta_wpa_psk_short **psk, char **identity, char **radius_cui)
{
	struct hostapd_cached_radius_acl *entry;
	struct os_reltime now;

	os_get_reltime(&now);

	for (entry = hapd->acl_cache; entry; entry = entry->next) {
		if (os_memcmp(entry->addr, addr, ETH_ALEN) != 0) {
			continue;
		}

		if (os_reltime_expired(&now, &entry->timestamp, RADIUS_ACL_TIMEOUT)) {
			return -1;    /* entry has expired */
		}
		if (entry->accepted == HOSTAPD_ACL_ACCEPT_TIMEOUT)
			if (session_timeout) {
				*session_timeout = entry->session_timeout;
			}
		if (acct_interim_interval) {
			*acct_interim_interval = entry->acct_interim_interval;
		}
		if (vlan_id) {
			*vlan_id = entry->vlan_id;
		}
		copy_psk_list(psk, entry->psk);
		if (identity) {
			if (entry->identity) {
				*identity = os_strdup(entry->identity);
			} else {
				*identity = NULL;
			}
		}
		if (radius_cui) {
			if (entry->radius_cui) {
				*radius_cui = os_strdup(entry->radius_cui);
			} else {
				*radius_cui = NULL;
			}
		}
		return entry->accepted;
	}

	return -1;
}
#endif							/* CONFIG_NO_RADIUS */

static void hostapd_acl_query_free(struct hostapd_acl_query_data *query)
{
	if (query == NULL) {
		return;
	}
	os_free(query->auth_msg);
	os_free(query);
}

#ifndef CONFIG_NO_RADIUS
static int hostapd_radius_acl_query(struct hostapd_data *hapd, const u8 *addr, struct hostapd_acl_query_data *query)
{
	struct radius_msg *msg;
	char buf[128];

	query->radius_id = radius_client_get_id(hapd->radius);
	msg = radius_msg_new(RADIUS_CODE_ACCESS_REQUEST, query->radius_id);
	if (msg == NULL) {
		return -1;
	}

	radius_msg_make_authenticator(msg, addr, ETH_ALEN);

	os_snprintf(buf, sizeof(buf), RADIUS_ADDR_FORMAT, MAC2STR(addr));
	if (!radius_msg_add_attr(msg, RADIUS_ATTR_USER_NAME, (u8 *)buf, os_strlen(buf))) {
		wpa_printf(MSG_DEBUG, "Could not add User-Name");
		goto fail;
	}

	if (!radius_msg_add_attr_user_password(msg, (u8 *)buf, os_strlen(buf), hapd->conf->radius->auth_server->shared_secret, hapd->conf->radius->auth_server->shared_secret_len)) {
		wpa_printf(MSG_DEBUG, "Could not add User-Password");
		goto fail;
	}

	if (add_common_radius_attr(hapd, hapd->conf->radius_auth_req_attr, NULL, msg) < 0) {
		goto fail;
	}

	os_snprintf(buf, sizeof(buf), RADIUS_802_1X_ADDR_FORMAT, MAC2STR(addr));
	if (!radius_msg_add_attr(msg, RADIUS_ATTR_CALLING_STATION_ID, (u8 *)buf, os_strlen(buf))) {
		wpa_printf(MSG_DEBUG, "Could not add Calling-Station-Id");
		goto fail;
	}

	os_snprintf(buf, sizeof(buf), "CONNECT 11Mbps 802.11b");
	if (!radius_msg_add_attr(msg, RADIUS_ATTR_CONNECT_INFO, (u8 *)buf, os_strlen(buf))) {
		wpa_printf(MSG_DEBUG, "Could not add Connect-Info");
		goto fail;
	}

	if (radius_client_send(hapd->radius, msg, RADIUS_AUTH, addr) < 0) {
		goto fail;
	}
	return 0;

fail:
	radius_msg_free(msg);
	return -1;
}
#endif							/* CONFIG_NO_RADIUS */

/**
 * hostapd_allowed_address - Check whether a specified STA can be authenticated
 * @hapd: hostapd BSS data
 * @addr: MAC address of the STA
 * @msg: Authentication message
 * @len: Length of msg in octets
 * @session_timeout: Buffer for returning session timeout (from RADIUS)
 * @acct_interim_interval: Buffer for returning account interval (from RADIUS)
 * @vlan_id: Buffer for returning VLAN ID
 * @psk: Linked list buffer for returning WPA PSK
 * @identity: Buffer for returning identity (from RADIUS)
 * @radius_cui: Buffer for returning CUI (from RADIUS)
 * Returns: HOSTAPD_ACL_ACCEPT, HOSTAPD_ACL_REJECT, or HOSTAPD_ACL_PENDING
 *
 * The caller is responsible for freeing the returned *identity and *radius_cui
 * values with os_free().
 */
int hostapd_allowed_address(struct hostapd_data *hapd, const u8 *addr, const u8 *msg, size_t len, u32 *session_timeout, u32 *acct_interim_interval, int *vlan_id, struct hostapd_sta_wpa_psk_short **psk, char **identity, char **radius_cui)
{
	if (session_timeout) {
		*session_timeout = 0;
	}
	if (acct_interim_interval) {
		*acct_interim_interval = 0;
	}
	if (vlan_id) {
		*vlan_id = 0;
	}
	if (psk) {
		*psk = NULL;
	}
	if (identity) {
		*identity = NULL;
	}
	if (radius_cui) {
		*radius_cui = NULL;
	}

	if (hostapd_maclist_found(hapd->conf->accept_mac, hapd->conf->num_accept_mac, addr, vlan_id)) {
		return HOSTAPD_ACL_ACCEPT;
	}

	if (hostapd_maclist_found(hapd->conf->deny_mac, hapd->conf->num_deny_mac, addr, vlan_id)) {
		return HOSTAPD_ACL_REJECT;
	}

	if (hapd->conf->macaddr_acl == ACCEPT_UNLESS_DENIED) {
		return HOSTAPD_ACL_ACCEPT;
	}
	if (hapd->conf->macaddr_acl == DENY_UNLESS_ACCEPTED) {
		return HOSTAPD_ACL_REJECT;
	}

	if (hapd->conf->macaddr_acl == USE_EXTERNAL_RADIUS_AUTH) {
#ifdef CONFIG_NO_RADIUS
		return HOSTAPD_ACL_REJECT;
#else							/* CONFIG_NO_RADIUS */
		struct hostapd_acl_query_data *query;

		/* Check whether ACL cache has an entry for this station */
		int res = hostapd_acl_cache_get(hapd, addr, session_timeout,
										acct_interim_interval,
										vlan_id, psk,
										identity, radius_cui);
		if (res == HOSTAPD_ACL_ACCEPT || res == HOSTAPD_ACL_ACCEPT_TIMEOUT) {
			return res;
		}
		if (res == HOSTAPD_ACL_REJECT) {
			return HOSTAPD_ACL_REJECT;
		}

		query = hapd->acl_queries;
		while (query) {
			if (os_memcmp(query->addr, addr, ETH_ALEN) == 0) {
				/* pending query in RADIUS retransmit queue;
				 * do not generate a new one */
				if (identity) {
					os_free(*identity);
					*identity = NULL;
				}
				if (radius_cui) {
					os_free(*radius_cui);
					*radius_cui = NULL;
				}
				return HOSTAPD_ACL_PENDING;
			}
			query = query->next;
		}

		if (!hapd->conf->radius->auth_server) {
			return HOSTAPD_ACL_REJECT;
		}

		/* No entry in the cache - query external RADIUS server */
		query = os_zalloc(sizeof(*query));
		if (query == NULL) {
			wpa_printf(MSG_ERROR, "malloc for query data failed");
			return HOSTAPD_ACL_REJECT;
		}
		os_get_reltime(&query->timestamp);
		os_memcpy(query->addr, addr, ETH_ALEN);
		if (hostapd_radius_acl_query(hapd, addr, query)) {
			wpa_printf(MSG_DEBUG, "Failed to send Access-Request " "for ACL query.");
			hostapd_acl_query_free(query);
			return HOSTAPD_ACL_REJECT;
		}

		query->auth_msg = os_malloc(len);
		if (query->auth_msg == NULL) {
			wpa_printf(MSG_ERROR, "Failed to allocate memory for " "auth frame.");
			hostapd_acl_query_free(query);
			return HOSTAPD_ACL_REJECT;
		}
		os_memcpy(query->auth_msg, msg, len);
		query->auth_msg_len = len;
		query->next = hapd->acl_queries;
		hapd->acl_queries = query;

		/* Queued data will be processed in hostapd_acl_recv_radius()
		 * when RADIUS server replies to the sent Access-Request. */
		return HOSTAPD_ACL_PENDING;
#endif							/* CONFIG_NO_RADIUS */
	}

	return HOSTAPD_ACL_REJECT;
}

#ifndef CONFIG_NO_RADIUS
static void hostapd_acl_expire_cache(struct hostapd_data *hapd, struct os_reltime *now)
{
	struct hostapd_cached_radius_acl *prev, *entry, *tmp;

	prev = NULL;
	entry = hapd->acl_cache;

	while (entry) {
		if (os_reltime_expired(now, &entry->timestamp, RADIUS_ACL_TIMEOUT)) {
			wpa_printf(MSG_DEBUG, "Cached ACL entry for " MACSTR " has expired.", MAC2STR(entry->addr));
			if (prev) {
				prev->next = entry->next;
			} else {
				hapd->acl_cache = entry->next;
			}
			hostapd_drv_set_radius_acl_expire(hapd, entry->addr);
			tmp = entry;
			entry = entry->next;
			hostapd_acl_cache_free_entry(tmp);
			continue;
		}

		prev = entry;
		entry = entry->next;
	}
}

static void hostapd_acl_expire_queries(struct hostapd_data *hapd, struct os_reltime *now)
{
	struct hostapd_acl_query_data *prev, *entry, *tmp;

	prev = NULL;
	entry = hapd->acl_queries;

	while (entry) {
		if (os_reltime_expired(now, &entry->timestamp, RADIUS_ACL_TIMEOUT)) {
			wpa_printf(MSG_DEBUG, "ACL query for " MACSTR " has expired.", MAC2STR(entry->addr));
			if (prev) {
				prev->next = entry->next;
			} else {
				hapd->acl_queries = entry->next;
			}

			tmp = entry;
			entry = entry->next;
			hostapd_acl_query_free(tmp);
			continue;
		}

		prev = entry;
		entry = entry->next;
	}
}

/**
 * hostapd_acl_expire - ACL cache expiration callback
 * @eloop_ctx: struct hostapd_data *
 * @timeout_ctx: Not used
 */
static void hostapd_acl_expire(void *eloop_ctx, void *timeout_ctx)
{
	struct hostapd_data *hapd = eloop_ctx;
	struct os_reltime now;

	os_get_reltime(&now);
	hostapd_acl_expire_cache(hapd, &now);
	hostapd_acl_expire_queries(hapd, &now);

	eloop_register_timeout(10, 0, hostapd_acl_expire, hapd, NULL);
}

static void decode_tunnel_passwords(struct hostapd_data *hapd, const u8 *shared_secret, size_t shared_secret_len, struct radius_msg *msg, struct radius_msg *req, struct hostapd_cached_radius_acl *cache)
{
	int passphraselen;
	char *passphrase, *strpassphrase;
	size_t i;
	struct hostapd_sta_wpa_psk_short *psk;

	/*
	 * Decode all tunnel passwords as PSK and save them into a linked list.
	 */
	for (i = 0;; i++) {
		passphrase = radius_msg_get_tunnel_password(msg, &passphraselen, shared_secret, shared_secret_len, req, i);
		/*
		 * Passphrase is NULL iff there is no i-th Tunnel-Password
		 * attribute in msg.
		 */
		if (passphrase == NULL) {
			break;
		}
		/*
		 * passphrase does not contain the NULL termination.
		 * Add it here as pbkdf2_sha1() requires it.
		 */
		strpassphrase = os_zalloc(passphraselen + 1);
		psk = os_zalloc(sizeof(struct hostapd_sta_wpa_psk_short));
		if (strpassphrase && psk) {
			os_memcpy(strpassphrase, passphrase, passphraselen);
			pbkdf2_sha1(strpassphrase, hapd->conf->ssid.ssid, hapd->conf->ssid.ssid_len, 4096, psk->psk, PMK_LEN);
			psk->next = cache->psk;
			cache->psk = psk;
			psk = NULL;
		}
		os_free(strpassphrase);
		os_free(psk);
		os_free(passphrase);
	}
}

/**
 * hostapd_acl_recv_radius - Process incoming RADIUS Authentication messages
 * @msg: RADIUS response message
 * @req: RADIUS request message
 * @shared_secret: RADIUS shared secret
 * @shared_secret_len: Length of shared_secret in octets
 * @data: Context data (struct hostapd_data *)
 * Returns: RADIUS_RX_PROCESSED if RADIUS message was a reply to ACL query (and
 * was processed here) or RADIUS_RX_UNKNOWN if not.
 */
static RadiusRxResult hostapd_acl_recv_radius(struct radius_msg *msg, struct radius_msg *req, const u8 *shared_secret, size_t shared_secret_len, void *data)
{
	struct hostapd_data *hapd = data;
	struct hostapd_acl_query_data *query, *prev;
	struct hostapd_cached_radius_acl *cache;
	struct radius_hdr *hdr = radius_msg_get_hdr(msg);

	query = hapd->acl_queries;
	prev = NULL;
	while (query) {
		if (query->radius_id == hdr->identifier) {
			break;
		}
		prev = query;
		query = query->next;
	}
	if (query == NULL) {
		return RADIUS_RX_UNKNOWN;
	}

	wpa_printf(MSG_DEBUG, "Found matching Access-Request for RADIUS " "message (id=%d)", query->radius_id);

	if (radius_msg_verify(msg, shared_secret, shared_secret_len, req, 0)) {
		wpa_printf(MSG_INFO, "Incoming RADIUS packet did not have " "correct authenticator - dropped\n");
		return RADIUS_RX_INVALID_AUTHENTICATOR;
	}

	if (hdr->code != RADIUS_CODE_ACCESS_ACCEPT && hdr->code != RADIUS_CODE_ACCESS_REJECT) {
		wpa_printf(MSG_DEBUG, "Unknown RADIUS message code %d to ACL " "query", hdr->code);
		return RADIUS_RX_UNKNOWN;
	}

	/* Insert Accept/Reject info into ACL cache */
	cache = os_zalloc(sizeof(*cache));
	if (cache == NULL) {
		wpa_printf(MSG_DEBUG, "Failed to add ACL cache entry");
		goto done;
	}
	os_get_reltime(&cache->timestamp);
	os_memcpy(cache->addr, query->addr, sizeof(cache->addr));
	if (hdr->code == RADIUS_CODE_ACCESS_ACCEPT) {
		u8 *buf;
		size_t len;

		if (radius_msg_get_attr_int32(msg, RADIUS_ATTR_SESSION_TIMEOUT, &cache->session_timeout) == 0) {
			cache->accepted = HOSTAPD_ACL_ACCEPT_TIMEOUT;
		} else {
			cache->accepted = HOSTAPD_ACL_ACCEPT;
		}

		if (radius_msg_get_attr_int32(msg, RADIUS_ATTR_ACCT_INTERIM_INTERVAL, &cache->acct_interim_interval) == 0 && cache->acct_interim_interval < 60) {
			wpa_printf(MSG_DEBUG, "Ignored too small " "Acct-Interim-Interval %d for STA " MACSTR, cache->acct_interim_interval, MAC2STR(query->addr));
			cache->acct_interim_interval = 0;
		}

		cache->vlan_id = radius_msg_get_vlanid(msg);

		decode_tunnel_passwords(hapd, shared_secret, shared_secret_len, msg, req, cache);

		if (radius_msg_get_attr_ptr(msg, RADIUS_ATTR_USER_NAME, &buf, &len, NULL) == 0) {
			cache->identity = os_zalloc(len + 1);
			if (cache->identity) {
				os_memcpy(cache->identity, buf, len);
			}
		}
		if (radius_msg_get_attr_ptr(msg, RADIUS_ATTR_CHARGEABLE_USER_IDENTITY, &buf, &len, NULL) == 0) {
			cache->radius_cui = os_zalloc(len + 1);
			if (cache->radius_cui) {
				os_memcpy(cache->radius_cui, buf, len);
			}
		}

		if (hapd->conf->wpa_psk_radius == PSK_RADIUS_REQUIRED && !cache->psk) {
			cache->accepted = HOSTAPD_ACL_REJECT;
		}

		if (cache->vlan_id && !hostapd_vlan_id_valid(hapd->conf->vlan, cache->vlan_id)) {
			hostapd_logger(hapd, query->addr, HOSTAPD_MODULE_RADIUS, HOSTAPD_LEVEL_INFO, "Invalid VLAN ID %d received from RADIUS server", cache->vlan_id);
			cache->vlan_id = 0;
		}
		if (hapd->conf->ssid.dynamic_vlan == DYNAMIC_VLAN_REQUIRED && !cache->vlan_id) {
			cache->accepted = HOSTAPD_ACL_REJECT;
		}
	} else {
		cache->accepted = HOSTAPD_ACL_REJECT;
	}
	cache->next = hapd->acl_cache;
	hapd->acl_cache = cache;

#ifdef CONFIG_DRIVER_RADIUS_ACL
	hostapd_drv_set_radius_acl_auth(hapd, query->addr, cache->accepted, cache->session_timeout);
#else							/* CONFIG_DRIVER_RADIUS_ACL */
#ifdef NEED_AP_MLME
	/* Re-send original authentication frame for 802.11 processing */
	wpa_printf(MSG_DEBUG, "Re-sending authentication frame after " "successful RADIUS ACL query");
	ieee802_11_mgmt(hapd, query->auth_msg, query->auth_msg_len, NULL);
#endif							/* NEED_AP_MLME */
#endif							/* CONFIG_DRIVER_RADIUS_ACL */

done:
	if (prev == NULL) {
		hapd->acl_queries = query->next;
	} else {
		prev->next = query->next;
	}

	hostapd_acl_query_free(query);

	return RADIUS_RX_PROCESSED;
}
#endif							/* CONFIG_NO_RADIUS */

/**
 * hostapd_acl_init: Initialize IEEE 802.11 ACL
 * @hapd: hostapd BSS data
 * Returns: 0 on success, -1 on failure
 */
int hostapd_acl_init(struct hostapd_data *hapd)
{
#ifndef CONFIG_NO_RADIUS
	if (radius_client_register(hapd->radius, RADIUS_AUTH, hostapd_acl_recv_radius, hapd)) {
		return -1;
	}

	eloop_register_timeout(10, 0, hostapd_acl_expire, hapd, NULL);
#endif							/* CONFIG_NO_RADIUS */

	return 0;
}

/**
 * hostapd_acl_deinit - Deinitialize IEEE 802.11 ACL
 * @hapd: hostapd BSS data
 */
void hostapd_acl_deinit(struct hostapd_data *hapd)
{
	struct hostapd_acl_query_data *query, *prev;

#ifndef CONFIG_NO_RADIUS
	eloop_cancel_timeout(hostapd_acl_expire, hapd, NULL);

	hostapd_acl_cache_free(hapd->acl_cache);
#endif							/* CONFIG_NO_RADIUS */

	query = hapd->acl_queries;
	while (query) {
		prev = query;
		query = query->next;
		hostapd_acl_query_free(prev);
	}
}

void hostapd_free_psk_list(struct hostapd_sta_wpa_psk_short *psk)
{
	while (psk) {
		struct hostapd_sta_wpa_psk_short *prev = psk;
		psk = psk->next;
		os_free(prev);
	}
}
